Sleep and chronotype during pregnancy, and the bright light treatment of perinatal depression

Background Perinatal depression (PND) is a severe mental disorder with disruptive consequences on the health and well-being of mothers, children, and their families. Due to the induced socioeconomic burden, it also represents a major public health problem for society as a whole, and is therefore considered a priority target of health prevention strategies at a global level. There is, in fact, general consensus among experts that PND is still prevalent, underrecognized and undertreated. While research on the pathophysiological mechanisms of PND is contributing to an increased knowledge of the multifactorial causes of this condition, and is likely to provide new biomarkers for medical use in the near future, none of these is currently available for the everyday clinical practice. Conversely, there is an urgent need of easy and universal screening instruments, as well as safe and affordable treatments that all women can have access to. Sleep and circadian rhythm disruption are commonly experienced by women during the perinatal period, but there is limited evidence on the objective changes in sleep parameters occurring during pregnancy and how these relate to health outcomes. Moreover, the role of sleep and circadian factors in the etiology of PND and as potential targets for treatment is still underestimated and underinvestigated. As an example, the influence of different circadian preferences for sleep-wake times (chronotypes) on the development of depressive symptoms across the perinatal period has never been investigated. Likewise, the efficacy and safety of bright light therapy (BLT) for the treatment of PND with onset before and/or after delivery have never been tested. Objectives Manuscript 1: to perform the first systematic review and meta-analysis of polysomnographic studies during pregnancy, in order to identify possible objective markers of sleep disruption in pregnant women. Manuscript 2: to investigate whether chronotype is a risk factor for PND and to explore the association between chronotype, maternal sociodemographic characteristics, and lifestyle habits, in relation to PND. Manuscript 3: to conduct the first randomized controlled trial (RCT) aimed at testing the efficacy and safety of BLT for PND occurring over a 12-month observation period. Methods Manuscript 1: by carefully following the PRISMA guidelines, we conducted the first systematic review of polysomnographic studies during pregnancy available in the literature. In addition, we performed a meta-analysis of the data collected on two sleep variables (TST and SE). This was instead not possible for other sleep parameters, due to the large heterogeneity of the reviewed studies. Manuscript 2: as a part of the “Life-ON” project, a multicenter, prospective, cohort study on sleep and mood changes during the perinatal period, 299 women were followed-up from the first trimester of pregnancy until 6 months postpartum. Chronotype was assessed at baseline using the MEQ, while mood was repeatedly evaluated at several timepoints with depression rating scales (i.e., EPDS, HDRS, and MADRS). The influence of time and chronotype on the different scales was estimated by constructing multilevel linear mixed regression models. A Cox proportional-hazard regression model was built to evaluate the association between chronotype and incidence of depression. Manuscript 3: in the frame of the “Life-ON” project, a RCT was conducted in a subsample of women with an EPDS score >12 at any time point from the second trimester of pregnancy up to 6 months postpartum. Participants received either BLT (10’000 lux) or DRL (19 lux) for 6 weeks, 30 minutes in the morning, within 20 minutes after wake up, and at a distance of 30 cm from the light box. Multilevel linear models were constructed to test for the influence of time and treatment group on EPDS values and log-linear models to test for socioeconomic factors influencing PND remission. Results According to our systematic review, the main changes in objective sleep parameters during pregnancy consists in a reduction of sleep duration and a fragmentation of sleep continuity, with an increased number of awakenings and superficial sleep stages (N1, N2), and a simultaneous decrease of SWS, REM sleep, and SE. The meta-analysis revealed a significant reduction of TST by 26.8 min between the first and third trimester of pregnancy, as well as a decrease of SE by 4% within the same time frame. Pregnant evening chronotypes, as compared to the other chronotypes, are more vulnerable to PND symptoms, especially in the immediate postpartum period. Although the survival analysis did not show a statistically significant influence of chronotype on the overall risk of PND, a trend towards an increased risk for PND in evening chronotypes and a reduced risk in intermediate types, as compared to morning types, was observed. Furthermore, in line with the literature, pregnant women with evening chronotype in the Life-ON study were more likely subject to health problems and negative pregnancy outcomes than the other chronotypes, and presented adverse sociodemographic characteristics and lifestyle attitudes, that are commonly associated with a higher risk for PND. Finally, in a RCT testing 6-week morning BLT (10’000 lux) vs. DRL (19 lux) for treating PND, the active light intervention (BLT) showed a remarkable efficacy in inducing a rapid remission from PND compared to DRL. The multilevel linear model revealed a significant influence of time on EPDS score and a group-time interaction, with a greater and sustained reduction in the BLT-group across the whole follow-up period. Conclusion We found evidence that the subjective experience of sleep deterioration, that many women report during pregnancy, is related to objective alterations in sleep architecture, particularly during late gestation. These can only be appropriately recorded by PSG, which should be therefore considered a valuable and sometimes necessary instrument to correctly diagnose sleep disorders, also during pregnancy, by overcoming under- or overestimation bias due to subjective reports of sleep problems. Interestingly, despite several physiological factors may be involved in the subjective worsening of sleep quality across gestation, is not pregnancy per se, that causes major PSG-assessed sleep disorders in healthy, normal-weight women. Rather, it is likely the combination of predisposing factors, such as obesity, higher maternal age or hypertension, and physiological changes occurring during pregnancy, that may contribute in particular to the development of obstructive sleep apnea (OSA) in at-risk pregnant women. Evening chronotype is associated with a time-dependent, greater severity of PND. Thus, assessing chronotype during pregnancy via the administration of an easy screening questionnaire, may help identify women who are likely to experience more severe perinatal depressive symptoms, especially in the early postpartum, and provide them with psychiatric/psychological support and treatment. BLT can not only induce a rapid and significant remission from PND compared to DRL, but the resulting improvement in mood can be maintained over time after treatment completion. These new findings support the integration of BLT as effective and safe chronotherapeutic tool, based on solid scientific evidence, to the equipment available to clinicians for the treatment of PND, thus responding to the need for affordable, easy-to-use, and accessible therapies for patients

Light, activity and sleep in my daily life: : Design of an online intervention targeting changes to routines and the home

Background: Older adults spend more time at home after retirement, and the home becomes a central place for activity. While research indicates that indoor lighting, exposure to daylight, physical activity and sleep interact to influence functioning, mood and daily rhythm, strategies are needed to promote behavioural changes to optimise these factors in daily life. The objective is to design an intervention delivered as a web-based course to encourage behaviour change related to outdoor physical activity, sleep patterns and changes to the home environment. The behaviour changes are intended to promote mental wellbeing and improve lighting and darkness conditions. The intervention strategy departs from the Information-Motivation-Behavioural Skills Model. Intervention components build on goal implementation theory. The Technology Acceptance Model is used as a framework to evaluate usability aspects of the course content and the learning management system. Method: Using a mixed-methods approach, qualitative and quantitative data were collected through video observations, semi-structured interviews and a 10-item Likert scale questionnaire (The System Usability Scale). Scores were averaged for each participant and converted into a usability score out of 100 (a score of 68 or above is considered above average). In a first round, three experts on pedagogy, design for older people and/or interaction design were invited to independently assess the usability of the course content on their laptops in a full-scale model of an apartment. The setting enabled manipulations of the lighting conditions (daylight mode and night mode, change of luminaires), contextual interviews and video observation to identify any problems when participants experimented with the test kit included in the course material. They participated on three occasions lasting 2 hours each. Six healthy adults (aged 70+) participated in a similar usability trial in a second round. Findings: Experts’ average usability score was 78.3, indicating “Good” usability. However, the interviews did reveal some issues (e.g. difficult or inconsistent terms, unclear instructions). Results were used to refine the course before the second usability trial with six participants. Based on the interviews and usability ratings, the participants were positive about the course, and the instructions were easy to follow. All six participants rated the overall user-friendliness of the course as 6 out of 7. The average usability score was 86.7, indicating “Excellent” usability. Based on the participants’ feedback and interactions in the apartment, changes to the course content included, e.g. clarifying terms, the different types of text links and instructions. Unexpected issues with online enrolment in the course appeared before the second trial because standard instructions developed by the university were not tailored to the participants.Conclusions: A two-step usability evaluation by experts in the first round and target users in the second proved valuable. It enabled refinement of the course content and significantly reduced the number of identified usability issues in the second trial. A learning management system seems promising for use in behaviour-change interventions. However, the time-limited lab trials restricted a complete evaluation. Therefore, the next step is to pilot the course and evaluate the feasibility in real-world homes

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 122, December 1973

This special bibliography lists 343 reports, articles, and other documents introduced into the NASA scientific and technical information system in November 1973

Evaluation of blue light exposure, illuminance level and the associations with sleep/wake patterns in two populations living with sensory impairment

Exposure to sufficient light during the daytime is fundamental for the regulation of the sleep/wake cycle, with the blue part of the spectrum most influential. This thesis explores exposure to environmental blue light and level of illuminance in two populations that experience circadian disruption i.e. older people and young people with autism spectrum disorder (ASD). The aim was to examine associations between blue light exposure, illuminance level and sleep/wake and physical activity patterns. Firstly, an exploratory study was conducted in adolescents with ASD living in a residential school setting aged 13-17 years (n=8). Secondly, a cross-sectional study carried out in two seasons (summer and winter) with a comparative study between seasons of varying light exposure and sleep/wake and physical activity outcomes was conducted in older people aged 72-99 years (n=20). In both studies quantitative measures were used to examine personal light exposure and sleep/wake patterns by use of novel equipment known as an actiwatch. This research demonstrated that objective measures of sleep/wake and light monitoring could be successfully administered in two populations with complex sensory issues. Preliminary findings from the exploratory study in adolescents with ASD indicated that exposure to blue light prior to bedtime was associated with a delay in sleep onset. The methodology developed for participant recruitment and engagement in a study using body sensors proved to be successful. Results for the study in older people suggested that between seasons daytime physical activity, blue light exposure and illuminance levels were significantly higher in summer. Correlated component regression (CCR) was used to investigate predictors of sleep parameters, suggesting morning blue light exposure (a predictor of total night-time sleep), daytime activity level (a predictor of sleep efficiency) and visual function (a predictor of minutes awake during the night) may contribute to sleep quality. The findings from these studies suggested that light exposure and health outcomes, such as physical activity and visual function could be responsible for sleep quality. This has important implications for design and health interventions promoting health and wellbeing, i.e. morning light exposure and time outdoors are important for circadian entrainment and building design and routine should reflect a diurnal light pattern light

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 182, July 1978

This bibliography lists 165 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1978

Evaluation and Design of Non-Lethal Laser Dazzlers Utilizing Microcontrollers

Current non-lethal weapons suffer from an inability to meet requirements for uses across many fields and purposes. The safety and effectiveness of these weapons are inadequate. New concepts have provided a weapon utilizing lasers to flashblind a target's visual system. Minimal research and testing have been conducted to investigate the efficiency and safety of these weapons called laser dazzlers. Essentially a laser dazzler is comprised of a laser beam that has been diverged with the use of a lens to expand the beam creating an intensely bright flashlight. All laser dazzlers to date are incapable of adjusting to external conditions automatically. This is important, because the power of these weapons need to change according to distance and light conditions. At long distances, the weapon is rendered useless because the laser beam has become diluted. At near distances, the weapon is too powerful causing permanent damage to the eye because the beam is condensed. Similarly, the eye adapts to brightness by adjusting the pupil size, which effectively limits the amount of light entering the eye. Laser eye damage is determined by the level of irradiance entering the eye. Therefore, a laser dazzler needs the ability to adjust output irradiance to compensate for the distance to the target and ambient light conditions. It was postulated if an innovative laser dazzler design could adjust the laser beam divergence then the irradiance at the eye could be optimized for maximum vision disruption with minimal risk of permanent damage. The young nature of these weapons has lead to the rushed assumptions of laser wavelengths (color) and pulsing frequencies to cause maximum disorientation. Research provided key values of irradiance, wavelength, pulsing frequency and functions for the optical lens system. In order for the laser dazzler to continuously evaluate the external conditions, luminosity and distance sensors were incorporated into the design. A control system was devised to operate the mechanical components meeting calculated values. Testing the conceptual laser dazzlers illustrated the complexities of the system. A set irradiance value could be met at any distance and light condition, although this was accomplished by less than ideal methods. The final design included two lasers and only one optical system. The optical system was only capable of providing constant irradiance of one laser or the other allowing only single laser operation. For dual laser operation, the optical system was calibrated to offset the losses of each laser as distance was changed. Ultimately, this provided a constant combined irradiance with a decreasing green irradiance and increasing red irradiance as distance was increasing. Future work should include enhancements to the mechanical components of the laser dazzler to further refine accuracy. This research was intended to provide a proof of concept and did so successfully

Influence of blue/green versus red and white light sources on human dark adaptation and other selected visual functions

Red interior lighting used to preserve dark-adaptation needs to be replaced in military applications by blue/green lighting which is not detectable by 3rd-generation image intensifiers. This study investigated the influence of blue/green as compared to red and white light of equal photopic intensity on subsequent visual acuity , contrast sensitivity and dark-adaptation. Male subjects (n = 90) were assigned to one of 15 treatment conditions (n = 6) as determined by the colour (blue/green, red or white) and intensity (0.1; 0.4; 1.6; 6.4 and 25.6 cd/m²) of the pre-adaptation stimuli. A modified Goldmann/Weekers adaptometer was used to present the preadaptation stimuli, test stimuli and record visual (luminance) thresholds of each subject. Blue/green lighting had the same affect on visual (photopic) acuity and contrast sensitivity as white and red lighting. Blue/green affected visual (absolute) threshold at the start and during the process of dark-adaptation in the same manner as white but not the same as red lighting. White and red lighting did not differ significantly (p < 0.01) at low intensities (mesopic range) but did at the higher intensities (photopic range). After exposure to blue/green and white light, it will take longer to reach the same level of dark-adaptation than after exposure to red. These time differences increase with" increased intensities. The brightness ratio between red and white lights to produce the same dark-adaptation increases with an increase in intensity. At the upper mesopic region the differences between the effects of white and red lighting on subsequent dark-adaptation become irregular due to the inability to accurately equate non-monochromatic lights in the mesopic range

ANALYSIS OF THE RELATIONSHIP BETWEEN IEQ AND ENERGY CONSUMPTION IN UAE UNIVERSITY BUILDING: IMPACT OF THERMAL AND LIGHTING COMFORT ON ENERGY USAGE

The Indoor Environment Quality (IEQ) of buildings becomes increasingly critical as people spend more than 90% of their time inside buildings based on the National Human Activity Pattern Survey (NHAPS) (Klepeis et al., 2001). The quality of the indoor environment in a building has been shown to have a significant impact on users\u27 productivity and energy consumption. Further, if tenants are working in a comfortable indoor environment, absenteeism rates and incidental expenses, such as medical expenses, will be reduced. For instance, a comfortable workplace increases productivity by 10-15% and reduces absenteeism by 2.5% (Leyten & Boerstra, 2003). According to the Intergovernmental Panel on Climate Change (IPCC) recent climate report, UAE residents are experiencing higher temperatures and harsher weather conditions (UAE MOCCAE, 2021). Research over the last years concluded that the longer people stay inside buildings, the more likely they are to be exposed to unhealthy environments. Which means more physical and psychological problems such as Sick Building Syndrome (SBS). The overtime spent inside also means more demands for energy inside the buildings.This thesis studied the relationship between Indoor Environmental Quality (IEQ) and energy use in a UAE university building. To assess IEQ levels, one of the university buildings was selected, and several IEQ parameters such as temperature, Relative Humidity (RH), Indoor Air Quality (IAQ), and illuminance were monitored. An online occupancy survey was distributed to users of the case study building to conduct a Post Occupancy Evaluation (POE) study. Dynamic simulation methods were applied to validate proposed changes based on monitoring and POE findings to improve comfort and energy efficiency, especially lighting and temperature.The main results of the survey can be summarized as follows: over 40% of students feel neutral on most parameters and are satisfied with their overall IEQ. However, students feel uncomfortable with the dry, stuffy air and the cold room temperature. When considering lighting comfort, 49% of students complain of too much artificial lighting and 32% complain of not enough daylight, and 51% are uncomfortable with glare and reflections. Regarding the results for Sick Building Syndrome (SBS), some students showed symptoms such as a runny nose, dry skin, headache, and fatigue. These symptoms are related to low room temperature, relative humidity, airflow from the AC system, and poor lighting.As a result of the monitoring experiment, lighting and temperature were found to be the most noticeable issues, which supports the results of the survey. The temperature in most classrooms was below 24 °C. Although most classrooms have plenty of natural light from morning to noon, daylight is not well utilized, resulting in the need for artificial lighting. It has also been observed that in most classrooms with tables and smartboards that are perpendicular to windows, factors such as glare and reflection arise. These factors reduce reliance on daylight and increase the use of artificial light.Simulation studies results show that the optimal solution to reduce energy consumption and improve occupant comfort is to increase the room temperature based on standards, change the classroom layout, increase daylight use and create artificial lighting zones. These changes result in saving 39% of the cooling load, 92% of artificial lighting, and 51% of total energy consumption.All the research findings are discussed in full detail in this thesis. The findings could be implemented in other UAE university buildings to improve IEQ, user comfort, and energy consumption